ALBERT

Description: Nizamoffite, ideally Mn 2+ Zn 2 (PO 4 ) 2 (H 2 O) 4 , is a new mineral from the Palermo No.1 pegmatite in North Groton, Grafton County, New Hampshire, U.S.A. It formed as the result of secondary alteration of primary triphylite and associated sphalerite. The crystals occur as colorless prisms up to 1 mm in length and 0.5 mm in diameter. The prisms are elongated and lightly striated parallel to [001] and exhibit the forms {100}, {010}, {230}, {011}, {031}, and {111}. The mineral is transparent and has a white streak, vitreous luster, Mohs hardness of about 31/2, brittle tenacity, irregular fracture, and three cleavages: perfect on {010}, good on {100}, and fair on {001}. The measured and calculated densities are 3.00(1) and 2.961 g/cm 3 , respectively. It is optically biaxial (–), α = 1.580(1), β = 1.590(1), = 1.591(1) (white light), 2 V meas = 28(1)°, and 2 V calc = 35°. Nizamoffite exhibits strong dispersion, r 〈 v . The optical orientation is X = a , Y = c , Z = b , and the mineral is nonpleochroic. Electron-microprobe analyses (average of 10), with H 2 O calculated on structural grounds, provided: CaO 0.20, MgO 0.61, MnO 15.80, ZnO 33.34, Fe 2 O 3 2.81, Al 2 O 3 0.10, P 2 O 5 32.05, H 2 O 15.95, total 100.23 wt%. The empirical formula (based on 12 O atoms) is: (Mn 2+ 0.99 Ca 0.02 ) 1.01 (Zn 1.82 Fe 3+ 0.12 Mg 0.07 ) 2.01 (P 1.00 O 4 ) 2 (H 1.96 O) 4 . The mineral dissolves readily in cold, dilute HCl. Nizamoffite is orthorhombic, Pnma , with the unit-cell parameters: a = 10.6530(4), b = 18.4781(13), c = 5.05845(15) Å, V = 995.74(8) Å 3 , and Z = 4. The eight strongest lines in the X-ray powder diffraction pattern are [ d obs in Å( I )( hkl )]: 9.27(71)(020); 4.62(37)(040,220); 4.43(24)(111); 3.424(52)(240,221); 2.873(100)(241); 2.644(36)(400,331); 2.540(33)(420,161,002); and 1.953(36)(281). Nizamoffite is isostructural with hopeite. The structure ( R 1 = 1.7% for 1014 F o 〉 4 F ) contains corner-sharing zigzag chains of ZnO 4 tetrahedra along [001]. The chains are connected by corner sharing with PO 4 tetrahedra to form sheets parallel to {010}. Three of the four PO 4 vertices link to ZnO 4 tetrahedra in the sheet, while the fourth links to an octahedron between the sheets. Each octahedron links to one tetrahedron from each of two adjacent sheets, thereby linking the sheets in the [010] direction. The octahedron contains Zn in hopeite and Mn in nizamoffite.

Description: Iangreyite, ideally Ca2Al7(PO4)2(PO3OH)2(OH,F)15{middle dot}8H2O, is anew mineral (IMA2009-087) from the Silver Coin mine, Nevada, USA and the Krasno ore district, Horni Slavkov, Czech Republic. At Silver Coin, iangreyite occurs as thin, colourless to white or cream, hexagonal tablets up to 0.4 mm in diameter and 0.02 mm thick associated with meurigite-Na, plumbogummite, kidwellite, lipscombite, strengite, chalcosiderite, wardite, leucophosphite, wavellite, goethite, barite, quartz and F-rich perhamite. At Krasno, white, yellowish or light pink iangreyite coatings consist of 0.3 mm wide clusters of minute and very thin intergrown tabular crystals with a maximum diameter of 0.2 mm. Individual iangreyite crystals are transparent with a vitreous lustre, while iangreyite clusters tend to be pearly and translucent. The estimated hardness is 3 on the Mohs scale, the fracture is irregular and the mineral is non-fluorescent under SW and LW ultraviolet light. Individual crystals are somewhat flexible and there is perfect cleavage on {001}. The density (Silver Coin), measured by the sink-float method in an aqueous solution of sodium polytungstate, is 2.46(3) g/cm3, while the calculated density is 2.451 g/cm3. Crystals from Silver Coin are uniaxial (+), with the indices of refraction: {omega} = 1.544(2) and {epsilon} = 1.554(2), measured in white light, and are non-pleochroic. The empirical formula for iangreyite from Silver Coin (calculated on the basis of 39 anions per formula unit) is: Ca1.42K0.22Na0.09Ba0.03Sr0.01Al6.51Mg0.09Fe0.02Cu0.01Zn0.01P3.81F5.24H30.21O33.76, while the empirical formula from Krasno is: Ca2.15K0.10Na0.01Ba0.02Sr0.12Al6.28Mg0.01Fe0.12Cu0.08Zn0.01P3.64Si0.43F4.65H29.62O34.35. Iangreyite is trigonal, space group P321 and Z = 1, with the unit-cell parameters (Silver Coin): a = 6.988(1), c = 16.707(3) A and V = 706.5(2) A3 and (Krasno): a = 6.989(1), c = 16.782(4) A and V = 709.8(2) A3. The structure of iangreyite, modelled from powder data, consists of blocks of the crandallite-type structure that are interconnected along c via corner-sharing of crandallite-block PO4 tetrahedra with AlO2(OH)3 bipyramids. This linkage generates large channels along [110] bounded by 10-member rings of octahedra, tetrahedra and trigonal biyramids, that are occupied by Ca and water molecules.

Description: Favreauite, ideally PbBiCu 6 O 4 (SeO 3 ) 4 · H 2 O, is a new secondary selenite mineral from the El Dragón mine, Antonio Quijarro Province, Potosí Department, Bolivia. The mineral occurs in vughs in a matrix of (Co, Cu)-rich penroseite, dolomite and goethite. Associated minerals are: ahlfeldite, allophane, calcite, chalcomenite, malachite, molybdomenite and an unnamed Al selenite. Favreauite forms tiny green square tabular crystals, flattened on {001}, up to 0.1 mm on edge and 0.01 mm thick, occurring in subparallel and divergent groups. The Mohs hardness of favreauite is estimated as 3; it has perfect cleavage on {001}, an irregular fracture and a vitreous lustre. The calculated density based on the empirical formula is 4.851 g cm –3 . Favreauite is uniaxial (–), with mean refractive index estimated as 1.854 from the Gladstone–Dale relationship. It is pleochroic in shades of green, O 〈 E . Electron microprobe analyses gave the empirical formula Pb 0.95 Ca 0.17 Bi 0.90 Cu 5.81 Se 4.10 O 16 (OH) · 1H 2 O, based on 18 O pfu . The Raman spectrum shows strong SeO 3 bands at 847 cm –1 ( 1 ), 764 and 795 cm –1 ( 3 ), 493 and 542 cm –1 ( 2 ), and 320 and 392 cm –1 ( 4 ). Favreauite is tetragonal, space group P 4/ n , with the unit-cell parameters: a = 9.860(4) Å, c = 9.700(5) Å, V = 943.0(9) Å 3 and Z = 2. The eight strongest lines in the X-ray powder diffraction pattern are [ d obs /Å ( I ) ( hkl )]: 5.67(100)(111), 3.470(76)(220,202), 3.190(35)(003), 2.961(40)(311,113), 2.709(33)(302,203), 2.632(34)(231,312), 2.247(36)(331,133), and 1.6652(33)(305,513,531). The crystal structure was refined to R 1 = 0.0329 for 1354 observed reflections [ F o 〉 4 F o ] and 0.0356 for all 1432 unique reflections. Favreauite is a close structural relative of nabokoite, KCu 7 Te 4+ O 4 (SO 4 ) 5 Cl, and atlasovite, KCu 6 Fe 3+ BiO 4 (SO 4 ) 5 Cl. In all cases, oxygen-centred tetrahedra share edges to form corrugated [Cu 6 M O 4 ] layers ( M = Bi or Te) which can be derived from the framework structure of murdochite, Pb 4+ Cu 2+ 6 O 8 - x (Cl,Br) 2 x by selective deletion of atoms. In favreauite, additional OH and H 2 O between the layers are weakly bound to Cu, giving it Jahn-Teller distorted 4 + 2 coordination. The Cu–Bi–O layer is braced by SeO 3 pyramids. The Bi 3+ and interlayer Pb 2+ form an approximately face-centred cubic array analogous to the Pb 4+ sites in murdochite. Unlike Bi 3+ , Pb 2+ is in a site with nonpolar $$\overline{4}$$ point symmetry, which suppresses the stereoactivity of its lone pair.

Description: Munakataite, Pb2Cu2(Se4+O3)(SO4)(OH)4, has been found in association with a variety of rare secondary Te minerals at Otto Mountain, San Bernardino County, California, USA. It is very rare and occurs as subparallel bundles of blue needles up to 1 mm long. Electron microprobe analyses provided the empirical formula Pb1.96Cu1.60[([IMG]f1.gif" ALT="Formula" BORDER="0"〉S0.11){Sigma}1O3](SO4)[(OH)3.34(H2O)0.66]{Sigma}4. Munakataite is monoclinic, space group P21/m, with cell parameters a = 9.8023(26), b = 5.6751(14), c = 9.2811(25) A, {beta} = 102.443(6), V = 504.2(2) A3 and Z = 2. The crystal structure, solved by direct methods and refined to R1 = 0.0308 for 544 Fo 〉 4{sigma}F reflections, consists of Jahn-Teller-distorted Cu2+O6 square bipyramids, which form chains along b by sharing trans edges across their square planes. The chains are decorated by SO4 tetrahedra and Se4+O3 pyramids, which bond to apical corners of adjacent bipyramids. The chains are linked to one another via bonds to two different PbO9 polyhedra, only one of which exhibits one-sided coordination typical of Pb2+ with a stereochemically active 6s2 lone-electron-pair. Munakataite is isostructural with schmiederite and the structure is closely related to that of linarite.

Description: The new mineral anorpiment, As2S3, the triclinic dimorph of orpiment, has space group P1I and cell parameters a = 5.7577(2), b = 8.7169(3), c = 10.2682(7) Å, a = 78.152(7), ß = 75.817(7), ? = 89.861(6)°, V = 488.38(4) Å3 and Z = 4. It occurs at the Palomo mine, Castrovirreyna Province, Huancavelica Department, Peru. It is a low-temperature hydrothermal mineral associated with dufrénoysite, muscovite, orpiment, pyrite and realgar. It occurs in drusy crusts of wedge-shaped, transparent, greenish yellow crystals. The streak is yellow. The lustre is resinous on crystal faces, but pearly on cleavage surfaces. The Mohs hardness is about 1. The mineral is sectile with an irregular fracture and one perfect and easy cleavage on {001}. The measured and calculated densities are 3.33 and 3.321 g cm-3, respectively. All indices of refraction are greater than 2. The mineral is optically biaxial (–) with 2V = 35–40° and no observed dispersion. The acute bisectrix (X) is approximately perpendicular to the {001} cleavage. Electron microprobe analyses yielded the averages and ranges in wt.%: As 58.21 (57.74–59.03), S 38.72 (38.33 39.00), total 96.94 (96.07 97.75), providing the empirical formula (based on 5 atoms) As1.96S3.04. The strongest powder X-ray diffraction lines are [d (hkl) I] 4.867(002) 97, 4.519 (110,11I1) 77, 3.702 (1I1I1) 46, 3.609 (022,11I2) 82, 2.880 (201,02I2,1I2I1,023) 75, 2.552 (1I13,1I31,132) 100, 2.469 (114,130,13I1) 96. The structure of anorpiment [R1 = 0.021 for 1484 reflections with Fo 〉 4s(F)] consists of layers of covalently bonded As and S atoms. Each S atom bonds to two As atoms at As–S–As angles between 100.45 and 104.15°. Each As atom is strongly bonded to three S atoms at S–As–S angles between 91.28 and 103.59°, forming an AsS3 pyramid with As at its apex. The As–S linkages within the layers form rings of six AsS3 pyramids. Interlayer bonding forces are interpreted as van der Waals. The structure of anorpiment is similar to that of orpiment in that it is composed of layers of As2S3 macromolecules, but arranged in a different stacking sequence.

Description: Bobmeyerite, Pb 4 (Al 3 Cu)(Si 4 O 12 )(S 0.5 Si 0.5 O 4 )(OH) 7 Cl(H 2 O) 3 , is a new mineral from the Mammoth–Saint Anthony mine, Tiger, Pinal County, Arizona, USA. It occurs in an oxidation zone assemblage attributed to progressive alteration and crystallization in a closed system. Other minerals in this assemblage include atacamite, caledonite, cerussite, connellite, diaboleite, fluorite, georgerobinsonite, hematite, leadhillite, matlockite, murdochite, phosgenite, pinalite, quartz, wulfenite and yedlinite. Bobmeyerite occurs as colourless to white or cream-coloured needles, up to 300 μm in length, that taper to sharp points. The streak is white and the lustre is adamantine, dull or silky. Bobmeyerite is not fluorescent. The hardness could not be determined, the tenacity is brittle and no cleavage was observed. The calculated density is 4.381 g cm –3 . Bobmeyerite is biaxial (–) with α β = 1.759(2), = 1.756(2) (white light), it is not pleochroic; the orientation is X = c ; Y or Z = a or b . Electron-microprobe analyses provided the empirical formula Pb 3.80 Ca 0.04 Al 3.04 $${\mathrm{Cu}}_{0.96}^{2+}$$ $${\mathrm{Cr}}_{0.13}^{3+}$$ Si 4.40 S 0.58 O 24.43 Cl 1.05 F 0.52 H 11.83 . Bobmeyerite is orthorhombic (pseudotetragonal), Pnnm with unit-cell parameters a = 13.969(9), b = 14.243(10), c = 5.893(4) Å, V = 1172.5(1.4) Å 3 and Z = 2. The nine strongest lines in the X-ray powder diffraction pattern, listed as [d obs (Å)( I )( hkl )], are as follows: 10.051(35)(110); 5.474(54)(011,101); 5.011(35)(220); 4.333(43)(121,211); 3.545(34)(040,400); 3.278(77)(330,231,321); 2.9656(88)(141,002,411); 2.5485(93)(051,222,501); 1.873(39)(multiple). Bobmeyerite has the same structural framework as cerchiaraite and ashburtonite. In the structure, which refined to R 1 = 0.079 for 1057 reflections with F 〉 4 F , SiO 4 tetrahedra share corners to form four-membered Si 4 O 12 rings centred on the c axis. The rings are linked by chains of edge-sharing AlO 6 octahedra running parallel to [001]. The framework thereby created contains large channels, running parallel to [001]. The Cl site is centred on the c axis alternating along [001] with the Si 4 O 12 rings. Two non-equivalent Pb atoms are positioned around the periphery of the channels. Both are eleven-coordinate, bonding to the Cl atom on the c axis, to eight O atoms in the framework and to two O (H 2 O) sites in the channel. The Pb atoms are off-centre in these coordinations, as is typical of Pb 2+ with stereo-active lone-electron pairs. A (S,Si,Cr)O 4 group is presumed to be disordered in the channel. The name honours Robert (Bob) Owen Meyer, one of the discoverers of the new mineral.

Description: The ideal formula for members of the cerchiaraite group is Ba 4 M 4 (Si 4 O 12 )O 2 (OH) 4 Cl 2 [Si 2 O 3 (OH) 4 ], where M represents Mn 3+ , Fe 3+ or Al in the octahedral site. A suffix-based naming scheme is used in which the original cerchiaraite is renamed cerchiaraite-(Mn) and two new minerals are named cerchiaraite-(Fe) and cerchiaraite-(Al). The type localities for cerchiaraite-(Fe) are the Cerchiara mine, Liguria, Italy and the Esquire No. 7 and No. 8 claims, Big Creek, Fresno County, California, USA. The type localities for cerchiaraite-(Al) are the Esquire No. 1 claim, Rush Creek, Fresno County, California, USA and the Esquire No. 7 and No. 8 claims noted above. At the Cerchiara mine, cerchiaraite-(Fe) occurs in small fractures and veinlets in a Jurassic ophiolitic sequence. It is of secondary hydrothermal origin and occurs as tan to brown thin prisms and matted fibres. Cerchiaraite-(Fe) and cerchiaraite-(Al) from the Esquire No. 1, No. 7 and No. 8 claims occur in parallel-bedded quartz-sanbornite vein assemblages which formed as a result of fluid interaction along the margin of the vein. At the Esquire No. 1, No. 7 and No. 8 claims, both cerchiaraite-(Fe) and cerchiaraite-(Al) occur as subparallel aggregates of blue to bluish green irregular prisms. Both minerals are transparent with a vitreous lustre, Mohs hardness ~41/2, brittle tenacity, irregular fracture and no cleavage. The calculated density of cerchiaraite-(Fe) is 3.710 g cm –3 ; the measured density of cerchiaraite-(Al) is 3.69(3) g cm –3 and the calculated density is 3.643 g cm –3 . Cerchiaraite-(Fe) is uniaxial (+), with = 1.741(2) and = 1.768(2); it is weakly pleochroic and O is colourless and E is yellow. Cerchiaraite-(Al) is uniaxial (–), with = 1.695(2) and = 1.677(2); it is strongly pleochroic and O is colourless and E is blue. Electron-microprobe analyses yielded empirical formulae ranging from (Ba 3.82 Na 0.02 Ca 0.04 ) 3.88 ( $${\mathrm{Fe}}_{3.42}^{3+}$$ $${\mathrm{Ti}}_{0.27}^{4+}$$ $${\mathrm{Al}}_{0.25}^{3+}$$ $${\mathrm{Mn}}_{0.04}^{3+}$$ Mg 0.02 ) 4.00 Si 5.62 O 15.47 (OH) 9.31 Cl 2.22 (Cerchiara mine) to Ba 4.00 ( $${\mathrm{Al}}_{2.40}^{3+}$$ $${\mathrm{Fe}}_{1.12}^{3+}$$ Mg 0.15 $${\mathrm{Fe}}_{0.12}^{2+}$$ $${\mathrm{Mn}}_{0.06}^{2+}$$ ) 3.85 Si 5.78 O 15.34 (OH) 8.75 Cl 2.91 (Esquire No. 1 claim). Cerchiaraite is tetragonal with Z = 2 and crystallizes in space group I 4/ mmm . The cell parameters for cerchiaraite-(Fe) are a = 14.3554(12), c = 6.0065(5) Å and V = 1237.80(5) Å 3 ; those for cerchiaraite-(Al) are a = 14.317(4), c = 6.0037(18) Å and V = 1230.6(6) Å 3 . In the cerchiaraite-(Fe) structure, SiO 4 tetrahedra share corners forming a four-membered Si 4 O 12 ring. The ring is corner-linked to an edge-sharing chain of Fe 3+ O 6 octahedra running parallel to c . A Cl site alternates along c with the Si 4 O 12 ring. A large channel in the framework contains Ba atoms around its periphery and statistically distributed Si 2 O 7 silicate dimers and Cl atoms. The strong blue pleochroic colour is attributed to Fe 2+ –Fe 3+ intervalence charge transfer along the octahedral chain.

Description: Cordylite-(La), (Na,Ca) 2 Ba 2 (La 3 Sr) 4 (CO 3 ) 8 F 2 , is a new mineral species (IMA2010–058) from the Biraya Fe–REE deposit, Irkutsk district, Russia. It occurs in direct association with barite, biraite-(Ce), niobium-rich chevkinite-(Ce), fergusonite-(Nd), ancylite-(Ce) and ancylite-(La), daqingshanite-(Ce) and daqingshanite-(La), bastnäsite-(Ce), hydroxylbastnäsite-(Ce), carbocernaite, monazite-(Ce), talc, humite, thorite, pyrite, and pyrrhotite in carbonate veins composed of aragonite, strontianite, calcite, dolomite, and cordylite-(Ce). Cordylite-(La) forms as colorless, honey-yellow, or pinkish yellow, irregularly-shaped, tabular, or short-prismatic hexagonal crystals up to about 3 mm across. The only forms observed are {100} and {0001} and crystals have perfect cleavage on {0001}. Crystals have a greasy to vitreous luster, a brittle tenacity, a conchoidal to uneven fracture, and a hardness of 4 on the Mohs scale. Crystals are uniaxial (–), = 1.573–1.574, and = 1.749–1.751. The empirical formula for two different crystals gave: (Na 1.24 Ca 0.78 ) 2.02 Ba 2.10 [(La 1.54 Ce 1.31 Nd 0.17 Pr 0.04 ) 3.06 Sr 0.89 ] 3.95 (C 1.01 O 3 ) 8 (F 1.78 OH 0.05 ) 1.83 and(Na 1.23 Ca 0.79 ) 2.02 Ba 1.98 [(La 1.43 Ce 1.33 Nd 0.25 Pr 0.10 ) 3.11 Sr 0.94 ] 4.05 (C 1.01 O 3 ) 8 (F 1.51 OH 0.38 ) 1.89 . The crystal structure, solved on the same two crystals ( R 1 = 0.0246 and 0.0205) gave the unit cell parameters in P 6 3 / mcc: a = 5.1182(5) and c = 23.1785(16) Å and V = 525.84(16) Å 3 and a = 5.1196(3) and c = 23.1784(16) Å and V = 525.13(5) Å 3 with Z = 1, and confirms that the mineral is isostructural with cordylite-(Ce). We also discuss new heterovalent substitution mechanisms found in the cordylite group minerals and the effect they have during the formation of crystals.

Description: Agaite, Pb 3 Cu 2+ Te 6+ O 5 (OH) 2 (CO 3 ), is a new tellurate from the Aga mine on Otto Mountain near Baker, California, U.S.A. The new mineral is known from only one specimen. It occurs on quartz in association with cerussite, Br-rich chlorargyrite, chrysocolla, goethite, khinite, markcooperite, muscovite, phosphohedyphane, timroseite, and wulfenite. It is interpreted as having formed from the partial oxidation of primary sulfides and tellurides during or following brecciation of quartz veins. Agaite is orthorhombic, space group Pca 2 1 , with unit-cell dimensions a = 10.6522(7), b = 9.1630(5), c = 9.6011(7) Å, V = 937.12(11) Å 3 , and Z = 4. Agaite crystals form as blades flattened on {010} and probably elongated on [001], and are up to about 20 μm thick and 200 μm in length. The color is blue, the streak is pale blue, and the luster is adamantine. The Mohs hardness is estimated at between 2 and 3. Agaite is brittle with an irregular fracture and one perfect cleavage on {010}. The calculated density based on the empirical formula is 6.987 g/cm 3 . Agaite is biaxial (–), with calculated indices of refraction of α = 2.015, β = 2.065, and = 2.070°. The measured 2 V is 34(5)° and the optical orientation is X = b , Y = c , and Z = a . It is pleochroic: X = pale blue, Y and Z = blue; X 〈 Y = Z . Electron microprobe analyses (average of 4) provided: PbO 65.91, CuO 7.75, TeO 3 17.41, CO 2 4.33 (structure), H 2 O 1.78 (structure), total 97.18 wt%. The empirical formula (based on 10 O apfu) is: Pb 3.00 Cu 2+ 0.99 Te 6+ 1.01 O 5 (OH) 2 (CO 3 ). The eight strongest powder X-ray diffraction lines are [ d obs in Å (hkl) I]: 4.26 (012) 28, 4.165 (211) 14, 3.303 (022, 310, 221) 100, 2.7472 (131, 203, 312) 68, 2.571 (032, 401, 231) 14, 2.0814 (332, 422) 21, 2.0306 (511) 17, and 1.7468 (multiple) 40. The crystal structure of agaite ( R 1 = 0.033 for 1913 reflections with F o 〉 4 F) contains edge-sharing chains of Cu 2+ O 5 square pyramids and Te 6+ O 6 octahedra parallel to a that are joined by corner-sharing in the c direction, forming a polyhedral sheet parallel to {010}. The polyhedral sheet is very similar to those in the structures of timroseite and paratimroseite. The thick interlayer region contains 8- and 9-coordinated Pb 2+ , as well as CO 3 and OH groups. The Pb coordinations have lopsided distributions of bond lengths attributable to the localization of the Pb 2+ 6s 2 lone-pair electrons.

Description: Fuettererite, Pb 3 Cu 6 2+ Te 6+ O 6 (OH) 7 Cl 5 , is a new tellurate from Otto Mountain near Baker, California, named for Otto Fuetterer who is largely responsible for the development of the mining claims on Otto Mountain. The new mineral is known from only two specimens, one from the NE2 vein and the other from the Bird Nest drift. Fuettererite occurs in vugs in quartz, on the first specimen associated with Br-rich chlorargyrite, iodargyrite, and telluroperite and on the second specimen associated with angle-site, anatacamite, atacamite, chalcopyrite, galena, goethite, hematite, muscovite, phosphohedyphane, timroseite, and wulfenite. It is interpreted as having formed from the partial oxidation of primary sulfides and tellurides during or following brecciation of quartz veins. Fuettererite is hexagonal, with space group R $$\overline{3}$$ , a = 8.4035(12), c = 44.681(4) Å, V = 2732.6(6) Å 3 , and Z = 6. Crystals are tabular to short prismatic, exhibit the forms {100}, {101}, and {001} and reach a maximum dimension of 50 μm. The color is bluish green, the streak is pale bluish-green, and the luster is adamantine. The Mohs hardness is estimated at between 2 and 3. The new mineral is brittle with irregular fracture and one perfect cleavage on {001}. The calculated density based on the empirical formula is 5.528 g/cm 3 . Fuettererite is uniaxial (–), with calculated indices of refraction of = 2.04 and = 1.97, and is dichroic bluish-green, E 〈 O. Electron microprobe analysis provided: PbO 41.45, CuO 30.35, Al 2 O 3 0.23, TeO 3 12.80, Cl 12.08, H 2 O 3.55 (structure), O=Cl –2.73, total 97.73 wt%. The empirical formula (based on 18 O + Cl apfu) is: Pb 2.88 Cu 5.92 2+ Al 0.07 Te 1.13 6+ O 6.59 (OH) 6.12 Cl 5.29 . The ten strongest powder X-ray diffraction lines are [ d obs in Å ( hkl ) I ]: 6.106 (104) 44, 3.733 (0.0.12) 100, 2.749 (12 $$\overline{1}$$ ) 53, 2.6686 (12 $$\overline{4}$$ ) 49, 2.5289 (12 $$\overline{7}$$ ) 41, 2.2772 (1.2.11) 38, 1.9637 (315, 1.2. $$\overline{16}$$ ) 87, 1.8999 (multiple) 48, 1.5976 (multiple) 40, and 1.5843 (410, 1.2.23, 143) 44. The crystal structure of fuettererite ( R 1 = 0.031 for 971 reflections with F o 〉 4 F ) contains edge-sharing sheets of CuO 5 Cl and TeO 6 octahedra. These sheets are virtually identical to that in the structure of spangolite, but in fuettererite they are linked together to form a double sheet. The double octahedral sheets alternate with thick double layers of PbO 2 Cl 6 polyhedra. The CuO 5 Cl octahedra exhibit pronounced Jahn-Teller distortions and the PbO 2 Cl 6 polyhedron has a lopsided distribution of bond lengths attributable to the localization of the Pb 2+ 6s 2 lone-pair electrons.